JP5181679B2 - Heating furnace and temperature control method for heated material - Google Patents

Description

  The present invention relates to a heating furnace for heating to a predetermined temperature when a slab or the like is hot-rolled, and a temperature control method for a material to be heated.

  A heating furnace is used to heat slabs, billets, blooms and the like after casting to a temperature suitable for hot rolling. Such a heating furnace is generally composed of a pre-tropical zone, a heating zone, and a soaking zone, and a material to be heated such as a slab is successively moved through the pre-tropic zone, the heating zone, and the soaking zone, to a predetermined temperature. It is configured so that it can be heated uniformly.

Recently, not only the material to be heated, such as a slab, is heated uniformly, but it is also heated so as to have a temperature gradient between the front end portion and the rear end portion of the slab.
For example, when manufacturing a thin rolled sheet, the time from the start of finish rolling of the slab tip to the start of finish rolling of the slab rear end becomes longer, during which the temperature drop at the slab rear end In some cases, the deformation resistance is increased, the shape is deteriorated due to load fluctuation, or the temperature is lower than a predetermined lower limit of the finishing rolling temperature. In such a case, in anticipation of the amount of temperature decrease, if inclined heating is performed to make the temperature at the rear end of the slab higher than the temperature at the front end, the load fluctuation at the rear end of the slab can be reduced, or a predetermined finish can be achieved. It becomes possible to perform rolling within the rolling temperature range.

  In addition, in order to improve productivity, after the slab tip is caught in the finish rolling mill, hot rolling may be performed at a gradually increased speed. The temperature increases at the rear end of the slab (rolled steel plate) after rolling, and scale wrinkles may occur or the upper limit of the finish rolling temperature may be exceeded. In such a case, in anticipation of an increase in the finish delivery temperature, if reverse gradient heating is performed to lower the temperature at the rear end of the slab to be lower than the temperature at the front end, the finish rolling exit temperature at the rear end of the slab is predetermined. This makes it possible to achieve both high quality and improved productivity of the rolled steel sheet.

  As a conventional heating furnace, for example, a heating furnace shown in FIG. This heating furnace has a plurality of pairs of regenerative combustion devices that alternately burn on both sides in the furnace length direction, a continuous combustion device in the width direction in the middle of the furnace length direction of the heating furnace, and the combustion amount of the continuous combustion device By adjusting the temperature, the temperature in the furnace width direction of the slab is uniformly or arbitrarily controlled.

Moreover, the heating furnace currently disclosed by patent document 2 arrange | positions the several pairs heat storage type combustion apparatus which carries out alternating combustion to the furnace length direction both sides, and sets the combustion time of the heat storage type combustion apparatus of one side to the heat storage of the other side. The slab is heated in an inclined manner by making it longer or shorter than the combustion time of the combustion chamber.
Japanese Patent Application Laid-Open No. 11-323431 JP 9-53115 A

  By the way, in the heating furnace of patent document 1, while arrange | positioning the roof burner which is a continuous combustion apparatus which can adjust combustion amount in a line along the furnace width direction of a heating zone, it follows along a furnace length direction. Not arranged. For this reason, there is a problem in that it is difficult to provide a gradient in the furnace temperature of the heating zone, and gradient heating or reverse gradient heating cannot be performed sufficiently.

  Further, in the heating furnace described in Patent Document 1, a regenerative heating apparatus for the main purpose of heating the slab uniformly in the heating furnace width direction (longitudinal direction of the material to be heated) is arranged further downstream of the roof burner. ing. For this reason, even if the amount of combustion of the roof burner installed in the heating zone is adjusted and the slab is inclined or heated reversely, the regenerative combustion device installed in the soaking zone along the furnace width direction As a result, the slab is heated uniformly, and it is difficult to increase the temperature gradient of the slab.

  Furthermore, in the heating furnace described in Patent Document 2, even if the combustion amount of the regenerative heating apparatus for originally heating the slab uniformly in the width direction of the heating furnace is changed within a controllable range, the slab has a large temperature. It was difficult to create a gradient.

  This invention is made | formed in view of the said situation, Comprising: It aims at provision of the temperature control method of the heating furnace and to-be-heated material which can perform inclined heating and reverse inclination heating reliably.

In order to achieve the above object, the present invention employs the following configuration.
Heating furnace of the present invention is charged with the material to be heated so as to be perpendicular to the conveying direction of the conveying path in the longitudinal direction of the material to be heated is provided in the heating furnace, along the material to be heated to the conveying path a heating furnace for heating while conveying Te, the under side of the transport path, the left and right sides of the conveying path toward the extraction side from the loading section side, a plurality of lower regenerative combustion alternating combustion An apparatus is disposed, and on the upper side of the conveyance path, in order to heat the entire material to be heated once and uniformly, on the left and right sides of the conveyance path from the loading section side to the middle of the conveyance path, alternating A plurality of upper regenerative combustion devices for combustion are disposed, and in order to perform inclined heating or reverse inclined heating on the extraction unit side from the installation position of the upper regenerative combustion device , along the furnace width direction It is divided into a plurality, and divided regions combustion quantity control a plurality of possible per Wherein the Continuous mixers combustion device is arranged.
Moreover, in the heating furnace of this invention, it is preferable that the ratio of the arrangement length along the furnace length direction of the said continuous combustion apparatus with respect to the total furnace length of a heating furnace is 15 to 80%.
Furthermore, in the heating furnace of the present invention, it is preferable that the continuous combustion apparatus is disposed in each of the regions divided into three or more along the furnace width direction.
In the heating furnace of the present invention, it is preferable that the regenerative burner is an FDI (fuel direct injection) type regenerative burner.

Next, the temperature control method of the heated material of the present invention is charged with the material to be heated so as to be perpendicular to the conveying direction of the conveying path in the longitudinal direction of the material to be heated is provided in the heating furnace, the object wherein the heating material by heating while being conveyed along the conveying path a temperature control method for controlling the temperature of the material to be heated, subjected to extraction side from the loading section side a lower side of the conveying path A plurality of lower-side regenerative combustion devices for alternating combustion are arranged on both the left and right sides of the transfer path, and the upper side of the transfer path and from the charging section side to the middle of the transfer path A plurality of upper regenerative combustion devices that alternately burn in order to uniformly heat the entire material to be heated are disposed on both the left and right sides, and further on the extraction unit side from the installation position of the upper regenerative combustion device A plurality of continuous combustion devices for performing gradient heating or reverse gradient heating. Respectively arranged in a plurality of regions divided along the furnace width direction, while uniformly heating the entire material to be heated by the upper and the lower regenerative combustion apparatus, by the continuous heating apparatus, the object to be by adjusting the combustion amount of the continuous combustion device for each of the areas divided along the chamber width direction in accordance with the target temperature distribution in the longitudinal direction of the heating member, control the longitudinal temperature of the material to be heated It is characterized by doing.

  According to the above heating furnace, first, since a plurality of regenerative heating devices that perform alternating combustion are provided, the material to be heated before being subjected to gradient heating or reverse gradient heating by the continuous combustion device is previously coated at a predetermined temperature. The entire heating material can be heated uniformly. A plurality of continuous combustion devices arranged in a plurality of regions along the furnace width direction and capable of controlling the amount of combustion for each region continue along the way from the middle of the conveyance path to the end of the extraction unit. Therefore, the temperature difference required for the furnace temperature can be set along the furnace width direction, and it becomes possible to perform the inclined heating or the reverse inclined heating to be applied to the material to be heated. .

  Further, according to the temperature control method for the material to be heated, first, the entire material to be heated is uniformly heated to a predetermined temperature by a plurality of regenerative heating devices that perform alternating combustion, and then, the end of the extraction unit from the middle of the conveyance path By a plurality of continuous heating devices arranged in a region divided into a plurality along the furnace width direction according to the target temperature distribution in the longitudinal direction of the material to be heated. Since the temperature of the heating material in the furnace width direction is controlled, it becomes possible to perform gradient heating or reverse gradient heating to be applied to the material to be heated.

ADVANTAGE OF THE INVENTION According to this invention, the heating furnace and the temperature control method of a to-be-heated material which can perform inclined heating and reverse inclination heating reliably can be provided.
Moreover, according to this invention, a required temperature difference can be provided to the front-end | tip part and rear-end part of a to-be-heated material at the time of performing gradient heating and reverse inclination heating.
Furthermore, according to the present invention, the temperature distribution of the material to be heated gradually has a smooth inclination, and a sudden temperature change of the material to be heated is reduced, so that a smooth temperature inclination can be obtained.

Hereinafter, a heating furnace and a temperature control method for a material to be heated, which are embodiments of the present invention, will be described with reference to the drawings. The drawings shown below are for explaining the configuration of the heating furnace, and the size, thickness, dimensions, and the like of each part shown in the drawings may differ from the actual dimensional relationship of the heating furnace.
1 is a schematic perspective view showing a heating furnace according to an embodiment of the present invention, FIG. 2 is a schematic side view of the heating furnace shown in FIG. 1, and FIG. 3 is a schematic plan view of the heating furnace shown in FIG. FIG. 4 is a schematic cross-sectional view corresponding to the line AA ′ of FIG.

As shown in FIGS. 1 to 4, the heating furnace 1 of the present embodiment extracts from the charging section 1 </ b> A and the conveying path 2 that sequentially conveys the material to be heated from the charging section 1 </ b> A side toward the extracting section 1 </ b> B side. The furnace chamber 3 provided along the conveyance path 2 up to the section 1B, the plurality of regenerative combustion devices 4 disposed on both sides in the conveyance direction of the conveyance path 2, and the extraction section 1B from the middle of the conveyance path 2 And a plurality of continuous combustion devices 5 arranged on the upper side of the conveying path 2.
In the heating furnace 1 of the present embodiment, when the material to be heated is continuously conveyed from the charging unit 1A side to the extraction unit 1B side by the conveyance path 2, first, the material to be heated is stored by the regenerative combustion device 4. The material to be heated is uniformly heated to a predetermined temperature, and then the material to be heated is subjected to gradient heating or reverse gradient heating so that the temperature along the longitudinal direction of the material to be heated has an inclination by the continuous combustion device 5.

  The to-be-heated material heat-processed by the heating furnace 1 of this embodiment is steel materials, such as a slab, billet, and bloom after casting. These materials to be heated are subjected to gradient heating or reverse gradient heating by the heating furnace 1 of the present embodiment, and then subjected to hot rolling by a hot rolling mill disposed at the subsequent stage of the heating furnace 1.

The material to be heated is continuously conveyed by the conveyance path 2 provided in the heating furnace 1. As the conveyance path 2, for example, a walking beam device or the like that can continuously convey the material to be heated can be used.
Further, the material to be heated is transported along the transport path 2 in a posture in which the longitudinal direction is directed in a direction substantially orthogonal to the transport direction. That is, the material to be heated is transported in such a posture that its longitudinal direction is along the furnace width direction.

Next, on both the left and right sides of the conveyance path 2, a plurality of regenerative combustion apparatuses 4 are arranged between the charging unit 1A and the extraction unit 1B. For example, an FDI type regenerative burner can be used as the heat storage combustion device 4. In the heating furnace 1 shown in FIGS. 1 to 4, the burner port 4 a of the regenerative combustion device 4 is arranged on the side wall surface 3 a of the furnace chamber 3, and the frame F blows out from the burner port 4 a along the furnace width direction. It has come to be.
Further, the regenerative combustion apparatus 4 is arranged side by side on the upper side and lower side of the transport path 2 in the transport direction of the transport path 2. With this configuration, the heated material can be heated from the upper side and the lower side when the heated material is conveyed along the conveyance path 2.

However, as shown in FIGS. 1 to 3, the regenerative combustion device 4 is not disposed on the upper side of the conveyance path 2 near the extraction unit 1 </ b> B where the continuous combustion device 5 is disposed. If the regenerative combustion apparatus 4 is arranged in the arrangement region of the continuous combustion apparatus 5, the material to be heated is uniformly heated by the regenerative combustion apparatus 4, and it becomes difficult to perform gradient heating or reverse gradient heating. It is not preferable.
On the other hand, a regenerative combustion device 4 is disposed below the conveyance path 2 near the extraction unit 1B in order to sufficiently heat the lower surface side of the material to be heated.

  Further, the regenerative combustion apparatus 4 is configured so as to alternately burn between the regenerative combustion apparatuses 4, 4 disposed opposite to both sides of the conveyance path 2, for example. When one heat storage type combustion device burns, the other heat storage type combustion device sucks the combustion gas, thereby heating the heat storage material built in the other heat storage type combustion device. Next, when the other heat storage type combustion apparatus is burned, the air for combustion is brought into contact with the heated heat storage material to preheat the air. By alternating combustion in this way, heat energy can be used efficiently. In addition, the combination of the regenerative combustion apparatus which carries out alternating combustion is not limited to what is arrange | positioned at the both sides of the conveyance path 2, For example, it is made to carry out alternating combustion between the regenerative combustion apparatuses arrange | positioned adjacent. Also good.

  In FIG. 5, the relationship between the furnace temperature by a thermal storage type combustion apparatus and a furnace width direction is shown with a graph. There are FDI type regenerative burners and gun type regenerative burners in the regenerative combustion apparatus. As shown in FIG. 5, it can be seen that the FDI type can make the temperature distribution in the furnace chamber more uniform than the gun type. . Therefore, it is preferable to use an FDI regenerative burner for heating the material to be heated by the regenerative combustion apparatus.

  Next, as shown in FIG. 1, the continuous combustion device 5 is located on the upper side of the conveyance path 2 and is continuously arranged along the furnace length direction from the middle of the conveyance path 2 to the extraction unit 1B. ing. Here, “continuous arrangement” refers to a state in which a plurality of continuous combustion apparatuses 5 are arranged side by side with a predetermined interval. The continuous combustion device 5 is located above the conveyance path 2, and more specifically, the burner port of the continuous combustion device 5 is disposed on the ceiling surface 3 b of the furnace chamber 3. The ceiling surface 3b on which the continuous combustion apparatus 5 is disposed is disposed closer to the transport path 2 than the other ceiling surface 3c. Moreover, as shown in FIGS. 1-4, the continuous combustion apparatus 5 is each arrange | positioned at the area | regions 5A-5D divided | segmented equally into four along the furnace width direction. As will be described later, the number of divisions is preferably three or more, and is not limited to four. These continuous combustion devices 5 can freely adjust the combustion amount, and can control the combustion amount for each of the regions 5A to 5D.

  The continuous combustion device 5 is a combustion device that blows out a flame continuously and burns it. The continuous combustion device 5 may be, for example, either a roof burner that blows the frame downward from the ceiling surface 3b of the furnace chamber 3 or an axial burner that blows the frame in the furnace length direction. A roof burner is good.

  The arrangement configuration of the continuous combustion device 5 will be described in more detail. As shown in FIGS. 1 to 3, the continuous combustion device 5 is along the furnace length direction from the middle of the conveyance path 2 to the extraction unit 1B. Are arranged consecutively. The arrangement length along the furnace length direction of the continuous combustion apparatus 5 is preferably 15% or more and 80% or less of the total furnace length of the heating furnace 1. That is, when the total furnace length of the heating furnace 1 is L, the length of the region where the continuous combustion apparatus 5 is disposed is preferably in the range of 0.15L to 0.80L.

  The ratio of the arrangement length along the furnace length direction of the continuous combustion apparatus 5 to the total furnace length of the heating furnace 1 depends on the temperature difference in the longitudinal direction of the material to be applied and the continuous type of the heating furnace 1. It is determined from the temperature difference in the furnace width direction of the furnace chamber 3 in which the combustion device 5 is disposed. The temperature difference in the longitudinal direction of the material to be heated is the temperature difference between the front end portion and the rear end portion in the longitudinal direction of the heated material after heating. The temperature difference in the furnace width direction of the furnace chamber 3 is a temperature difference between the highest temperature and the lowest temperature on the conveyance path 2 when the combustion amount of the continuous heating device 5 is controlled along the furnace width direction. When determining the lower limit of the required arrangement length of the combustion apparatus 5, the maximum temperature difference determined by the capacity of the combustion apparatus and the durability of the refractory in the heating furnace is determined. FIG. 6 shows the case where the temperature at the front end of the heated material at the time of extraction in the heating furnace is 1200 ° C. and the temperature difference in the furnace width direction of the furnace chamber in which the continuous combustion apparatus is arranged is 100 ° C. The relationship between the ratio of the arrangement length along the furnace length direction of the continuous combustion apparatus 5 to the total furnace length of the heating furnace 1 and the longitudinal temperature difference of the material to be heated is shown in a graph. The temperature difference in the longitudinal direction of the material to be heated has only to be about 30 ° C. from the past results. If the conditions in FIG. 6 are satisfied, the ratio of the arrangement length along the longitudinal direction of the continuous combustion device 5 should be 15% or more. I know it ’s good. When the temperature difference in the furnace chamber 3 is smaller than 100 ° C., the ratio of the arrangement length may be increased. However, as the ratio of the arrangement length of the continuous combustion apparatus 5 increases, it becomes disadvantageous for energy saving. % Is the upper limit.

Moreover, the continuous combustion apparatus 5 is each arrange | positioned at several area | region 5A-5D divided | segmented along the furnace width direction, as shown in FIGS. In the present embodiment, an example in which the number of regions is four is shown, but the number of regions is preferably 3 or more, and more preferably 3 to 5.
In one region, a plurality of continuous combustion apparatuses 5 are arranged in two rows along the furnace length direction. As shown in FIG. 4, the continuous combustion apparatuses 5 arranged in two rows are in pairs. That is, the continuous combustion apparatus 5 is connected to the two fuel gas supply paths 6 a and 6 b branched from the single fuel gas supply path 6.
The continuous combustion apparatus 5 can adjust the combustion amount for each of the regions 5A to 5D. For example, the continuous combustion device in the region 5A on one end side in the furnace width direction is burned with a certain rated combustion amount, and the continuous combustion device in the adjacent region 5B is burned with a smaller combustion amount than the region 5A, Similarly, the combustion amount can be gradually reduced in the regions 5C and 5D. Thereby, it is possible to incline the furnace temperature of the furnace chamber 3 under the continuous combustion apparatus 5 along the furnace width direction. Thereby, for example, the temperature difference between the maximum temperature and the minimum temperature in the longitudinal direction of the heated material on the conveyance path 2 can be set to 30 ° C. or more.

The amount of combustion for each of the regions 5A to 5D of the continuous combustion apparatus needs to be adjusted according to the target temperature distribution in the longitudinal direction of the material to be heated. For example, in the target temperature distribution in the longitudinal direction of the material to be heated, the heating target temperature at the front end of the material to be heated is t ₁ ° C, and the heating target temperature at the rear end is t ₂ ° C (for example, t ₁ > t ₂ ). Suppose that the temperature between the front end portion and the rear end portion is a temperature distribution that changes at a predetermined rate along the longitudinal direction of the material to be heated. In this case, the combustion amount for each of the regions 5A to 5D of the continuous combustion apparatus has an arrangement length along the longitudinal direction of the continuous combustion apparatus 5 so that the temperature distribution after heating of the material to be heated matches the target temperature distribution. The ratio may be adjusted so that the temperature difference in the furnace chamber 3 is optimal.

FIG. 7 is a graph showing the relationship between the longitudinal position of the material to be heated that has been reversely inclined heated so that the temperature at the rear end is lower than the temperature at the front end, and the temperature difference between when the material is uniformly heated. This graph shows the temperature distribution in the longitudinal direction of the heated material when the continuous combustion device 5 is divided into 2 to 5 regions along the furnace width direction and the heated material is heated. is there. The longitudinal position of the material to be heated, which is the horizontal axis in FIG. 7, represents the distance from the front end portion in the longitudinal direction when the total length in the longitudinal direction of the material to be heated is 1. For example, a position where the longitudinal position is 0.2 indicates a position separated from the longitudinal end by a distance of 1/5 (= 0.2) of the entire length. Moreover, the temperature difference with the uniform heating which is the vertical axis in FIG. 7 represents the difference with the temperature of the heated material when the temperature when the heated material is heated uniformly is used as a reference (zero). . In FIG. 7, the material to be heated is heated when the heating is performed so that the temperature of the rear end (longitudinal position = 1.0) of the material to be heated is 30 ° C. lower than the temperature of the front end (longitudinal position = 0). The temperature distribution of the material is shown.
As shown in FIG. 7, the temperature distribution of the material to be heated gradually has a smooth slope by sequentially increasing the number of divisions when arranging the continuous combustion apparatus 5 along the furnace width direction from 2 to 5. I understand that For example, when the number of divisions is 2, the temperature of the material to be heated is rapidly changed in the range where the longitudinal position is 0.4 to 0.6, but when the number of divisions is 3 or more, the temperature of the material to be heated is Therefore, it is preferable to divide into three or more regions.

  Note that the control of the combustion amount is not limited to the case where the combustion amount is sequentially decreased from the region 5A to the region 5D as described above, and the combustion amount may be sequentially increased from the region 5A to the region 5D. Further, uniform heating may be performed with the same amount of combustion in the regions 5A to 5D.

  Further, the continuous combustion apparatus may be further divided into a plurality of regions along the furnace length direction, and the combustion amount in the furnace width direction may be adjusted for each region divided along the furnace length direction.

Next, the temperature control method of the material to be heated by the heating furnace 1 of the present embodiment will be described.
First, the heating furnace 1 shown in FIG. 1 thru | or FIG. 4 is prepared, and the slab after casting is prepared as a to-be-heated material, for example. And a slab (material to be heated) is charged from the charging portion 1A. When the slab is charged, the slab is charged in such a posture that the longitudinal direction of the slab is orthogonal to the transfer direction of the transfer path provided in the heating furnace. The charged slab is transported along the transport path 2 in the furnace chamber 3 toward the extraction unit 1B. At this time, the slab (material to be heated) is uniformly heated by the regenerative combustion devices 4 arranged on both sides of the conveyance path 2 in the conveyance direction.

  Next, the slab heated uniformly by the regenerative combustion device 4 is transported along the transport path 2 to a region where the continuous combustion device 5 is disposed. As shown in FIGS. 1 to 4, the continuous combustion apparatus 5 is disposed in the regions 5 </ b> A to 5 </ b> D divided into a plurality along the furnace width direction. The combustion amount of the combustion chamber 5 is controlled for each of the regions 5A to 5B. For example, the control is performed so that the combustion amount is sequentially decreased from the region 5A toward the region 5D. Thereby, the furnace temperature of the furnace chamber 3 becomes the highest in the vicinity of the region 5A, and the temperature gradually decreases toward the region 5D side. By transporting the slab (material to be heated) through the interior of the furnace chamber 3 in such a state, the temperature of the tip of the slab on the region 5A side is higher than the temperature of the rear end of the slab on the region 5D side. Heated to be high. Further, the temperature of the slab is inclined between the front end portion and the rear end portion of the slab. In this way, the slab (material to be heated) is subjected to gradient heating or reverse gradient heating.

  As described above, according to the heating furnace 1 of the present embodiment, since a plurality of regenerative heating devices that perform alternating combustion are provided first, the object to be heated before the gradient heating or the reverse gradient heating is performed by the continuous combustion device. The whole material to be heated can be uniformly heated to a predetermined temperature in advance. A plurality of continuous combustion devices 5 arranged in a plurality of regions along the furnace width direction and capable of controlling the amount of combustion for each region extend along the way from the middle of the conveyance path 2 to the end of the extraction unit 1B. Therefore, it is possible to make a necessary temperature difference in the furnace temperature along the furnace width direction, and to perform inclined heating or reverse inclined heating to be applied to the material to be heated. it can.

In addition, the ratio of the arrangement length along the furnace length direction of the continuous combustion device 5 to the total furnace length of the heating furnace 1 should be 15% or more, preferably 15% or more and 80% or less, so that it should be given to the material to be heated. Inclination heating or reverse inclination heating can be performed, and the temperature difference between the front end portion and the other end portion of the heated material can be made sufficient.
Furthermore, since the continuous combustion apparatus 5 is arrange | positioned in the area | region divided | segmented into 3 or more along the furnace width direction, it can heat so that the temperature distribution of a to-be-heated material may have a gradually smooth inclination.
Furthermore, if the heat storage combustion device 4 is an FDI type regenerative burner, the material to be heated before being heated by the continuous combustion device can be heated uniformly.

Moreover, according to the temperature control method of the material to be heated according to the present embodiment, the entire material to be heated is uniformly heated to a predetermined temperature by a plurality of regenerative heating devices that perform alternating combustion, and the extraction unit 1B is moved from the middle of the conveyance path 2. According to the target temperature distribution in the longitudinal direction of the material to be heated, by a plurality of continuous heating devices 5 arranged continuously in the furnace width direction and arranged in a plurality of regions along the furnace width direction. Since the temperature of the material to be heated in the furnace width direction is controlled, it is possible to perform gradient heating or reverse gradient heating to be applied to the material to be heated.
A plurality of continuous combustion devices 5 arranged in a region divided into a plurality along the furnace width direction are continuously provided along the furnace length direction from the middle of the conveyance path 2 to the end of the extraction unit 1B. Since they are arranged, uniform heating is not performed on the material to be heated that is heated at an inclination, and the temperature gradient of the material to be heated can be increased.

  A heating furnace having the structure shown in FIGS. 1 to 4 was prepared with the furnace length, the furnace width, the arrangement length along the furnace length direction of the continuous combustion apparatus, and the installation pitch of the continuous combustion apparatus set as shown in Table 1 below. . The heating furnace is divided into four zones along the conveying direction of the material to be heated, and is referred to as a first heating zone, a second heating zone, a third heating zone, and a soaking zone from the charging side. In the heating furnaces A to C, a roof burner is disposed as a continuous combustion device on the third heating zone close to the extraction side and above the soaking zone, and a heat storage combustion device is disposed in the other region, The ratio of the arrangement length along the furnace length direction of the continuous combustion apparatus to the total furnace length was 50%, and the number of divisions in the furnace length direction of the continuous combustion apparatus was two. In the heating furnace D, a roof burner is arranged on the upper side of the soaking zone, and a regenerative burner is arranged in the other area, and the arrangement length along the furnace length direction of the continuous combustion apparatus with respect to the entire furnace length of the heating furnace The ratio was 15%. The number of divisions in the furnace width direction of the continuous combustion apparatus of the heating furnaces A, C, and D was four. The number of divisions in the furnace width direction of the continuous combustion apparatus of the heating furnace B was two. Further, the roof burners of the heating furnaces A, B, and D were FDI type, and the roof burner of the heating furnace C was a gun type.

  As a material to be heated, as shown in Table 2, slabs having a length of 13.0 to 13.2 m, a width of 1.0 to 1.1 m, and a thickness of 250 to 251 mm were prepared. In this example, the temperature of the slab when charged in the heating furnace was set to two levels of 20 ° C. and 600 ° C.

The heating target temperatures of the slab tip and the rear end are as shown in Table 2. Inclined heating that raises the temperature of the rear end than the slab tip and the reverse that lowers the temperature of the rear end than the slab tip Inclined heating was performed. In order to heat the slab to the target temperature, the furnace temperature in each zone of the heating furnace is as shown in Table 3, and in the center in the furnace length direction and the center in the furnace width direction of each zone where the regenerative burner is arranged. Combustion while observing the temperature measurement results of the furnace thermometer (not shown) placed and the furnace thermometer (not shown) placed in the center of the zone divided in the furnace width direction of the zone where the continuous combustion device is placed The combustion amount of the device was adjusted. In addition, the 3rd heating zone and soaking zone furnace temperature of Table 3 are the furnace temperature of the upper part side which installed the continuous combustion apparatus, and divided | segmented four area | regions into a front-end | tip part, the center part 1, the center part 2, It is referred to as the rear end, and indicates the furnace temperature for each region. However, the furnace thermometer of the heating furnace B divided into two in the furnace width direction was installed at the same position as the heating furnace divided into four. The furnace temperature on the lower side where the regenerative combustion apparatus was arranged was 1250 ° C. in the third heating zone and 1220 ° C. in the soaking zone.
Table 4 shows the results of measuring the front end temperature and the rear end temperature of the slab immediately before extraction from the heating furnace. The temperature of the front end portion and the rear end portion of the slab is a result of measurement using a radiation thermometer at a position of about 300 mm from the end portion on the upper surface side of the slab immediately before extraction from the heating furnace. As shown in Table 4, gradient heating or reverse gradient heating could be carried out with a temperature difference substantially equal to the target.

  As is apparent from the present example, according to the heating furnace of the present invention, it can be seen that the temperature difference between the front end and the rear end of the 13 m long heated material can be 30 ° C.

FIG. 1 is a schematic perspective view showing a heating furnace according to an embodiment of the present invention. FIG. 2 is a schematic side view of the heating furnace shown in FIG. FIG. 3 is a schematic plan view of the heating furnace shown in FIG. FIG. 4 is a schematic sectional view corresponding to the line A-A ′ of FIG. 3. FIG. 5 is a graph showing the relationship between the furnace temperature and the furnace width direction by the regenerative combustion apparatus. FIG. 6 is a graph showing the relationship between the ratio of the arrangement length of the continuous combustion apparatus to the total furnace length of the heating furnace and the longitudinal temperature difference deviation of the material to be heated. FIG. 7 is a graph showing the relationship between the longitudinal position of the material to be heated and the temperature difference between uniform heating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heating furnace, 1A ... Charge part, 1B ... Extraction part, 2 ... Conveyance path, 4 ... Regenerative combustion apparatus, 5 ... Continuous combustion apparatus

Claims (5)

Heating the longitudinal direction of the material to be heated is charged with the material to be heated so as to be perpendicular to the conveying direction of the conveying path provided in the heating furnace, it is heated while the material to be heated is conveyed along the conveying path A furnace,
On the lower side of the conveying path, a plurality of lower regenerative combustion devices for alternating combustion are arranged on the left and right sides of the conveying path from the charging unit side to the extraction unit side,
On the upper side of the conveying path, a plurality of upper sides that alternately burn on both the left and right sides of the conveying path from the charging portion side to the middle of the conveying path in order to uniformly heat the entire material to be heated. A regenerative combustion device of
Wherein said extracting portion than the installation position of the upper regenerative combustion apparatus, in order to perform a heat ramp or inverse slope heated is divided into a plurality along the furnace width direction, and the combustion amount of each divided area furnace, characterized in that the control is a plurality of continuous combustion device capable are arranged.   2. The heating furnace according to claim 1, wherein a ratio of an arrangement length along a furnace length direction of the continuous combustion apparatus to a total furnace length of the heating furnace is 15% or more and 80% or less.   The heating furnace according to claim 1 or 2, wherein the continuous combustion apparatus is disposed in each of three or more regions divided along the furnace width direction.   The heating furnace according to any one of claims 1 to 3, wherein the regenerative burner is an FDI type regenerative burner. Said charged material to be heated so as to be perpendicular to the conveying direction of the conveying path in the longitudinal direction of the material to be heated is provided in the heating furnace, the heating while conveying along the material to be heated to the conveying path And a temperature control method for controlling the temperature of the heated material,
On the left and right sides of the transfer path from the charging section side to the extraction section side below the transfer path, a plurality of lower regenerative combustion devices for alternating combustion are arranged ,
On the left and right sides of the transfer path from the loading section side to the middle of the transfer path, the upper side of the transfer path is a plurality of alternating combustions to temporarily heat the entire material to be heated. A thermal storage combustion device is installed,
Further, a plurality of continuous combustion devices for performing inclined heating or reverse inclined heating on the extraction unit side from the installation position of the upper regenerative combustion device are divided into a plurality of regions along the furnace width direction. Place each in
The entire heated material is uniformly heated by the upper and lower regenerative combustion devices, and along the furnace width direction according to the target temperature distribution in the longitudinal direction of the heated material by the continuous heating device. by adjusting the combustion amount of the continuous combustion device for each of the areas divided Te, the temperature control method of the material to be heated, characterized in that to control the longitudinal temperature of the material to be heated.

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